Could anyone please refer me to any documentation/example of setting up Order workflow with administrator's intervention to approve CC charge while using Drupal7/Ubercart3.

Here's the my use case -
Once in a while supplier doesn't have item that he supposed to send or item should be back-ordered. In this case both - store owner and customer suffer by having charge/refund
Store owner wants instead of charging customer's credit card immediately and then refunding him in case of supplier failure to have option to Approve or Cancel order after inventory confirmation and before it passed to gateway.
So that workflow would be - "add to cart, place order, order approved/canceled, payment processed, item shipped".

This depends on the gateway you have chosen, but you may be be able to select "Authorisation only" instead of "Authorise and capture immediately" in the payment gateway settings, which will let your administrator only take funds from the customer's account when they are ready to do so. The way you eventually capture the payment and the amount of time you have to do so varies between gateways.

Since I'm planning to use Authorize.net I checked their API documentation first and found exactly what I need in Advanced Integration Method (AIM) (which btw is included in a basic Auth.net $20/month package).
When using AIM methodology you have two relevant methods -AUTH_ONLY where you provide CC details and amount and get TRANSACTION ID# that can be stored on your website and will expire in 30 days (this is what happens when customer click PROCEED WITH CHARGE)PRIOR_AUTH_CAPTURE can complete AUTH_ONLY transaction. You just provide TRANSACTION ID# and perform actual amount CAPTURE (this is what happens when you click APPROVE CHARGE)

The only caveat hear is that this will work "either all or nothing" meaning that if you have authorization for $XXX amount for YY-items you either APPROVE all or CANCEL all.
You cannot remove just "Item 1" and change updated Amount. In this case you'll need to authorize again (i.e. provide CC details and new amount)
But if store owner is OK to have this as an exception (that can be handled by manual contacting customer) AIM is the solution.

Now back to Ubercart. It looks like AIM is supported by uc_auth module.
While I'm mostly MS/.NET-guy I'm installing Zend environment to be able to debug and fully understand the process below the hood.
In worst case I will have to dig in to PHP and do it myself or.....may be even move from Drupal to something else. Payment system is extremely important part in e-commerce solution. So far I found Ubercart not very mature or friendly. While you must agree payment system has to work like Swiss watch here.

Now Ubercart is integrated with eBay payment gateway. It support for the eBay token API, eBay Beagle anti-fraud.now you can process your order easily.
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Hello sir ! thanks for this information, first thing there should have an expiration time or date if an item is need to be back in this case you can prevent any malicious refund from the customer.Increase Datpiff Views.